{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,4]],"date-time":"2025-12-04T06:59:34Z","timestamp":1764831574207,"version":"3.46.0"},"reference-count":40,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T00:00:00Z","timestamp":1764547200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"crossref","award":["2025M773132"],"award-info":[{"award-number":["2025M773132"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Nansha District People\u2019s Livelihood Science and Technology Plan","award":["2024MS016"],"award-info":[{"award-number":["2024MS016"]}]},{"name":"Nansha-South China Agricultural University Fishery Research Institute","award":["NSYYKY202301"],"award-info":[{"award-number":["NSYYKY202301"]}]},{"DOI":"10.13039\/501100003453","name":"Natural Science Foundation of Guangdong Province","doi-asserted-by":"crossref","award":["2024A1515012835"],"award-info":[{"award-number":["2024A1515012835"]}],"id":[{"id":"10.13039\/501100003453","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Guangzhou Science and Technology Project","award":["SL2024A04J02066"],"award-info":[{"award-number":["SL2024A04J02066"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The mud crab (Scylla paramamosain), an economically important crustacean aquaculture species in southern China, is susceptible to infections due to its immune system lacking acquired immunity. An emergent disease locally termed \u201cpus crab\u201d has caused severe muscle lesions in pond-farmed crabs, but its etiology remained unclear. Here, we applied an integrated approach, histopathology, electron microscopy, metagenomic sequencing, and experimental infection to identify the pathogen of \u201cpus crab\u201d. Histological staining (H&amp;E, Wright\u2013Giemsa, and Masson) revealed muscle fiber dissolution, disordered fiber arrangement, and abundant interstitial spore-like bodies. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed intracellular spore morphology consistent with microsporidia. Metagenomic profiling showed a pronounced shift in the muscle microbiome, with a marked increase in microsporidian taxa at the genus level and a concurrent decline in bacterial relative abundance. Functional annotation indicated enrichment of pathways related to protein processing, ribosome biogenesis, glycosylation, and the ubiquitin\u2013proteasome system. Isolation of spores from diseased muscle and subsequent injection into healthy crabs reproduced wild-like clinical signs and histopathology, confirming infectivity and implicating microsporidia as the likely etiological agents of \u201cpus crab\u201d. These findings establish a multidisciplinary framework for pathogen identification in aquaculture and provide candidate molecular and biochemical markers for early diagnosis and management.<\/jats:p>","DOI":"10.3390\/ani15233463","type":"journal-article","created":{"date-parts":[[2025,12,3]],"date-time":"2025-12-03T08:44:28Z","timestamp":1764751468000},"page":"3463","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Integrative High-Throughput Screening and Microscopic Evidence Implicates Microsporidia as a Potential Pathogen of \u201cPus Crab\u201d in the Mud Crab (Scylla paramamosain)"],"prefix":"10.3390","volume":"15","author":[{"given":"Lanfei","family":"Xiao","sequence":"first","affiliation":[{"name":"Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 511464, China"},{"name":"College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yongjun","family":"Liang","sequence":"additional","affiliation":[{"name":"Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 511464, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shuangli","family":"Hao","sequence":"additional","affiliation":[{"name":"College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5199-9921","authenticated-orcid":false,"given":"Kun","family":"Wu","sequence":"additional","affiliation":[{"name":"Nansha-South China Agricultural University Fishery Research Institute, Guangzhou 511464, China"},{"name":"College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"739885","DOI":"10.1016\/j.aquaculture.2023.739885","article-title":"Comparative transcriptomic analysis provided insights into the local molecular responses of swimming crabs, Portunus trituberculatus and mud crabs, Scylla paramamosain to the infection of Ameson portunus (Microsporidia)","volume":"576","author":"Xin","year":"2023","journal-title":"Aquaculture"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.aquaculture.2009.02.003","article-title":"White spot syndrome virus quantification in blue crab Portunus trituberculatus hatchery-produced larvae and wild populations by TaqMan real-time PCR, with an emphasis on the relationship between viral infection and crab health","volume":"291","author":"Meng","year":"2009","journal-title":"Aquaculture"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"742827","DOI":"10.1016\/j.aquaculture.2025.742827","article-title":"The parasitic dinoflagellate Hematodinium perezi suppresses the innate immunity of Portunus trituberculatus via exosomal miRNAs","volume":"609","author":"Zhang","year":"2025","journal-title":"Aquaculture"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"112184","DOI":"10.1016\/j.marpolbul.2021.112184","article-title":"Health risks associated with sulfonamide and quinolone residues in cultured Chinese mitten crab (Eriocheir sinensis) in China","volume":"165","author":"Fang","year":"2021","journal-title":"Mar. 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